A group of Nebraska farmers is suing the giant seed and chemical company, Monsanto, in federal court saying the company’s top-selling herbicide gave them cancer.

Farmers Larry Domina, Robert Dickey, and Royce Janzen, along with farm agronomist Frank Pollard, have each been diagnosed with non-Hodgkins lymphoma, a type of blood cancer. They were exposed to Monsanto’s Roundup weedkiller in their work on the farm.

They allege that Roundup caused their illness and that Monsanto downplayed research showing the chemical poses a cancer risk.

The two conclusions don’t necessarily contradict each other. IARC judges whether it is at all possible for a chemical to cause cancer, while the JMPR considers the risk of developing cancer from the levels of pesticide residue on food.

Roundup is one of the most heavily used weedkillers in the country. Most of the corn and soybeans planted in the U.S. are genetically modified to withstand Roundup so farmers can kill weeds but not their crop.

A possible deal was announced this week that could have a lasting impact on American farmers, reports Harvest Public Media. The monolithic agricultural company Monsanto has proposed a deal to purchase the world’s largest pesticide company, Syngenta. Monsanto has said that it aims to find new ways to combine chemicals and biotech crops. In an effort to expand, the company has been recently been buying up a lot of tech companies.

With rootworms building resistance to genetically modified corn that makes its own pesticide, seed companies are working on new crops that target the insects’ genes. But some worry about unintended consequences when the technology moves from the lab to the field.

With “bulletproof” weeds like palmer amaranth and kochia becoming ever more resistant across the Great Plains, farmers must focus on rotating modes of action, using pre-emergent herbicides and following the label when mixing products, experts say.

Farmers engaged in an epic struggle with “superweeds” – weeds that don’t die even when sprayed with herbicide – are looking for help from a new super chemical that’s about to hit the market.

Currently the last line of defense against weeds not felled by other herbicides, the new chemical could be defeated if it is overused and farmers could be left in even worse straits.

Pigweed Problem

Herbicide-resistant Pigweeds are marching north into soybean and corn fields across the Midwest from the southern U.S. where they choked cotton fields so completely that the land cannot be farmed They can grow up to seven feet tall and produce more than half a million seeds per plant, per season.